Hypodermic syringe



Feb- 9, 1954 N. B. JoRGENsEN HYPODERMIC SYRINGE Filed Aug. 9, 1952 l/f/ l/// l INVENToR. NIE/ 5 JOPGENSEN 3 In the form of the invention shown in Fig. 1, the lateral wall 20 of bulb I9 has its inner wall aligned with and forming a continuation of the wall of cavity 23 in sleeve I6.

In the modified form of the invention shown in Fig. 4, bulb I9a has an outer diameter equal to or less than the diameter of cavity 23.

In the operation of the invention, after the ampule has been inserted into the syringe and the yoke II) moved to an operative position with plnuger I3 in alignment with the axis of barrel 8, the syringe is immediately ready for use. After the needle has been inserted into a patients body, if the operator desires to test whether a blood vessel has been pierced, he carefully presses the plunger I3 inwardly, collapsing bulb I9 against shoulder 22. The starting position is shown in Fig. 1 and the end of this initial stage of operation is shown in Fig. 3. Thereupon, by releasing the pressure against plunger I3, the bulb I9, being of resilient material, will regain its original form shown in Fig. l and in doing so will draw back into the syringe the amount of fluid that was initially expelled therefrom. The volume of bulb I9 is regulated to provide for withdrawing a sulicient amount of iiuid to bring into the transparent cylinder Ill enough blood to make the same visibleto the operator. in the event a vessel has been punctured.

The advantage of the invention over earlier devices of this type that are designed for use in a standard syringe, resides in the fact that the extremely thin walled bulb I9 may be collapsed with only a very slight amount of pressure on plunger I3, much less than would be required to stretch a diaphragm of the same thickness into the cavity 23. A further advantage resides in the fact that the bulb maybe made of any desired depth to provide the required volume of initial ejection and Withdrawal, without increasing the force that must be applied thereto in order to fully collapse the bulb. Accordingly, the likelihood of the skirt I6 slipping in the cylinder Id under the load applied to the initial ejection and withdrawal device (bulb I9) is eliminated, and it becomes possible to provide an even looser fit of the skirt I6 in the cylinder I4, and consequently a smoother and easier piston action when the stopper is pushed forwardly in the iinal syringe action.

After the testing operation has been completed, the operator again advances the plunger I3 until the bulb I9 is fully collapsed against shoulder 22. Further movement of plunger I3 will then be transmitted through shoulder 22 to skirt I6, since the inner end of plunger I3 is of larger diameter than the diameter of cavity 23.

The operation in the form shown in Fig. 1i is the same as in the other form, of the invention, with the exception that bulb. II9a, being of an outer diameter equal to or less than the diameter of cavity 23, is adapted to enter cavity 23 until it is completely received therein, as indicated in dotted lines in Fig. 4, and plunger I3 is thereby permitted to engage directly with shoulder 22, as also indicated in dotted lines.

It will be understood that the stopper of my invention is constructed from soft rubber or equivalent material, including some of the thermoplastic resin (such as the vinyl plastic).

I claim:

1. A component for a hypodermic syringe having a plunger, a piston, and a cylinder in which said piston is operable: said component consisting in a medicant ampule including a barrel adapted to function as said cylinder and a stopper in one end of said barrel adapted to function as said piston, said stopper being integrally molded of a resilient material having the characteristics of soft rubber, and including an annular relatively thick walled skirt received in and in sealing engagement with the wall of said barrel, said skirt having an axial cavity, open at its inner end, and a bulb on the outer end of said skirt, having a cavity formed as a continuation of said skirt cavity, the outer end of said skirt defining, at the base of said bulb, an annular external shoulder extending from said bulb radially outwardly to the lateral face of said skirt, said bulb being adapted to be engaged by the inner end of said plunger and collapsed in an initial range of plunger movement, while the skirt remains iixed in the cylinder, and being form regaining after plunger pressure is released, whereby to eiiect a suction for drawing back into the syringe a quantity of iiuid equal to that discharged therefrom in the collapsing of the bulb, said bulb having a Wall thickness only a fraction of that of said skirt, having an outer diameter equal to or less than the diameter of said skirt cavity, and being adapted, during said collapsing, to be displaced into said skirt cavity so that said plunger may directly engage said annular shoulder for advancing said stopper in said barrel.

2. A component for a hypodermic syringe having a plunger, a piston, and a cylinder in which said piston is operable: said component consisting in a medicant ampule including a barrel adapted to function as said cylinder and a stopper in one end of said barrel adapted to function as said piston, said stopper being integrally molded of a resilient materia-l having the characteristics of soft rubber, and including an annular relatively thick walled skirt received in and in sealing engagement with the wall of said barrel, said skirt having an axial cavity, open at its inner end, and a bulb on the outer end o said skirt, having a cavity formed as a continuation of said skirt cavity, the outer end of said skirt dening, at the base of said bulb, an annular external shoulder extending from said bulb radially outwardly to the lateral face of said skirt, said bulb being adapted to be engaged by the inner end of said plunger and collapsed in an initial range of plunger movement, while the skirt remains iixed in the cylinder, and being form regaining after plunger pressure is released, whereby to eiect a suction for drawing back into the syringe a quantity of fluid equal to that discharged therefrom in the collapsing of the bulb, said bulb having a wall thickness only a fraction of that of said skirt, having an outer diameter substantially the same as the diameter o said skirt cavity, and being adapted, during said collapsing, to be displaced into said skirt cavity so that sa d plunger may directly engage said annular shodlder for advancing said stopper in said barrel.

NIELS BJ ORN J ORGENSEN.'

References Cited in the iile of this patent UNITED STATES PATENTS Number Name Date 2,460,039 Scherer et al. Jan. 25, 1949 2,556,331 Lockhart July 12, 1951 

